Surgical clips and methods for tissue approximation

ABSTRACT

Surgical clips, and methods of use thereof, are provided for tissue approximation and attachment, and more particularly, for sealingly joining a graft vessel to a target vessel. The graft vessel has a free end and a graft vessel wall defining a graft lumen. The target vessel has a target vessel wall defining a target lumen and has an opening in the target vessel wall. The anastomosis clip includes a clip body having a distal extremity with a distal end and a proximal extremity with a proximal end. The distal end is configured to penetrate through the graft vessel wall near the free end and through the target vessel wall near the opening such that both the distal and proximal ends of the clip body are outside the graft and target vessels. At least a portion of the clip body is shapable so as to compress the graft vessel wall against the target vessel wall with the target vessel lumen in communication with the graft vessel lumen.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation of copending application Ser.No. 08/598,513, filed Feb. 8, 1996, which is a continuation-in-part ofcopending application Ser. No. 08/394,333, filed Feb. 24, 1995, thecomplete disclosure of which is hereby incorporated herein by referencefor all purposes.

FIELD OF THE INVENTION

[0002] The present invention relates generally to surgical instrumentsand methods, and more specifically to devices and methods for surgicalwound closure, tissue approximation and attachment, and vascularanastomosis, especially coronary artery anastomosis.

BACKGROUND OF THE INVENTION

[0003] In coronary artery disease, one or more of the coronary arterieswhich supply oxygenated blood to the heart are partially or entirelyblocked by a build-up of atherosclerotic plaque within the artery. Thisdeprives the heart muscle of oxygen and nutrients, leading to myocardialinfarction and even death.

[0004] Coronary artery bypass grafting remains the gold standard for thesurgical treatment of severe coronary artery disease. In coronary arterybypass grafting, or CABG, a graft vessel is used to bypass a blockage ina coronary artery by connecting the distal end of the graft vessel tothe coronary artery downstream of the blockage and connecting theproximal end of the graft vessel to a source of arterial blood upstreamof the blockage. Various types of graft vessels may be used, including asaphenous vein taken from the patient's leg, a radial artery removedfrom the patient's forearm, or a prosthetic graft made of expandedpolytetrafluoroethylene, Dacron, or other suitable material.Additionally, the left or right internal mammary arteries, whichoriginate from the subclavian artery and reside on the top of the chestwall, may be resected at a distal location and left intact proximally,the free distal end then being connected to the diseased coronary arterydownstream of the blockage. Similarly, the gastroepiploic artery, whichoriginates from the gastroduodenal artery in the abdomen, may beresected at a distal location in the abdomen and passed into the thoraxthrough a puncture in the diaphragm for attachment to the diseasedcoronary artery. Other types of graft vessels may also be used, as wellas combinations of several different types of graft vessels in order tobypass multiple coronary blockages.

[0005] The surgical interconnection of two vascular structures, such asa graft vessel and a coronary artery, is a process known as anastomosis.In CABG, the anastomosis of a graft vessel to a coronary artery isparticularly challenging. Several factors contribute to this challenge.First, the scale of the vessels is extremely small, the coronaryarteries having a diameter on the order of about 1-5 mm, and the graftvessels having a diameter on the order of about 1-4 mm for an arterialgraft such as a mammary artery, or about 4-8 mm for a vein graft. Inaddition, the completed anastomosis must not only provide a sealedconnection and a patent blood flow path between the graft vessel and thecoronary artery, but must further provide a connection which minimizesthe exposure of the blood to foreign material or external vesselsurfaces which can cause thrombosis at the anastomosis site. Moreover,recent studies suggests that the anastomosis site should not bedramatically different in compliance relative to either the coronaryartery or the vascular graft, since such a “compliance mismatch” mayalso cause thrombus to form at the anastomosis.

[0006] Suturing is the technique of choice for coronary anastomosis inthe vast majority of CABG cases today. The anastomosis is performed bycreating a small opening, or arteriotomy, in the coronary artery, andpassing a series of running stitches through the walls of the graftvessel and the coronary artery, respectively, around the perimeter ofthe arteriotomy so as to compress the end of the graft vessel againstthe side wall of the coronary artery. The surgeon has a great deal offlexibility in selecting the optimum location for each stitch, based onthe shape, structure and condition of the two vessels. The suture needlemay be placed initially through the graft vessel wall, and, before thetwo vessels are closely approximated, the needle then independentlyplaced through the desired location in the target vessel wall. Thesuture is then tensioned to approximate the two vessels and create atight, hemostatic seal. The sutured anastomosis thus offers a secure,sealed and patent connection between the two vessels, while having asubstantial degree of compliance due to the flexible nature of thesuture material.

[0007] A drawback of the sutured anastomosis is, however, the highdegree of skill, dexterity, and acute visualization required. Inaddition, the completion of the anastomosis takes a significant amountof time, during which the patient is maintained under cardioplegicarrest and cardiopulmonary bypass. The period of cardioplegic arrestshould generally be minimized in order to minimize damage to the heartmuscle. Further, in recent years, some attempts have been made atreducing the invasiveness and trauma of CABG surgery by working throughsmaller incisions or “ports” between the ribs and using endoscopicsurgical techniques. Performing microvascular anastomoses withconventional sutures is extremely difficulty when working through smallports, particularly if direct vision of the anastomosis site is notpossible and reliance upon endoscopic visualization techniques isnecessitated.

[0008] Various ideas have been proposed for simplifying and acceleratingthe process of coronary anastomosis using sutureless anastomosisdevices. For example, in U.S Pat. No. 4,350,160 to Kolesov et al., adevice is disclosed for creating an end-to-end anastomosis by evertingeach vessel end over a split bushing and driving a plurality of staplesthrough the everted vessel ends. For coronary anastomosis, this devicerequires that the coronary artery be severed downstream of the blockageand the downstream end dissected away from the surface of the heart inorder to allow it to be connected end-to-end to the graft vessel. Thisadds an undesirable increase in time, difficulty and risk to theprocedure. In addition, the staples in the Kolesov device are alwayspositioned in a fixed pattern, allowing no flexibility in selecting thelocation in which each staple is to be driven through the vessels.

[0009] In U.S. Pat. No. 4,624,257 to Berggren et al., a device isdisclosed for creating either end-to-end or end-to-side anastomoses. Thedevice consists of a pair of rigid rings each having a central openingthrough which the end of the coronary or graft vessel may be drawnthrough and everted over the ring. A set of sharp pins extend outwardlyfrom the face of each ring and pierce through the vessel wall tomaintain the vessel in the everted configuration. The rings are thenjoined together to align the end of the graft vessel with the opening inthe target vessel. While this device may be suitable for end-to-sideanastomosis, eliminating the need to sever and isolate a free end of thecoronary artery, the device requires that the side wall of the coronaryartery be everted through the central opening of the ring, a maneuverwhich is likely to be extremely difficult in coronary anastomosis due tothe structure and size of the coronary arteries. Moreover, the use ofrigid rings that completely encircle the graft vessel and thearteriotomy creates a severe compliance mismatch at the anastomosis sitewhich could lead to thrombosis.

[0010] An additional device which has been proposed for end-to-sideanastomosis is seen in U.S. Pat. No. 5,234,447 to Kaster et al. Thisdevice consists of a rigid ring having a plurality of pointed legsextending from the ring axially in the distal direction and a pluralityof angled legs extending axially from the ring in the proximaldirection. The graft vessel is placed through the middle of the ring andthe end is everted over the pointed legs, which puncture the vessel walland retain it on the ring. The pointed legs are then bent outwardly, andthe everted end of the graft vessel and the outwardly-oriented pointedlegs are inserted through an arteriotomy in the target vessel so thatthe pointed legs engage the interior wall of the target vessel. Theangled legs on the proximal end of the ring are then bent toward thetarget vessel to penetrate the outer wall thereof. While the Kasterdevice has a simple one-piece design and avoids the need to evert thewall of the target vessel over the device as proposed in Berggren, thedevice maintains a rigid ring structure which results in inadequatecompliance at the anastomosis. In addition, the rigidity of Kaster'sdevice leaves the surgeon little flexibility in selecting the optimumlocation where each leg of the device should be driven into the graftand target vessels, in contrast to the flexibility available whenplacing suture stitches.

[0011] U.S. Pat. No. 4,586,503 to Kirsch et al. discloses an alternativescheme for creating microvascular anastomoses. The Kirsch deviceconsists of a plurality of individual clips each consisting of a pair ofarcuate legs interconnected by a bridging section. The edges of thevascular tissue to be anastomosed are approximated and everted outwardlyso that a clip can be placed over the tissue edges, and the clip is thencrimped to permanently deform the legs in an inward position. The clipthereby retains the edges of the tissue together without puncturing thetissue. A plurality of clips are placed around the graft vessel in thismanner to accomplish the anastomosis. The Kirsch device eliminates thecompliance problems of rigid ring-type devices, and allows the surgeonthe flexibility to select the optimum location for the placement of eachclip. However, the Kirsch clips suffer from several disadvantages. Forexample, placement of the clips while maintaining eversion andapproximation of the tissue edges is difficult and time-consuming.Typically, two pairs of forceps are needed to hold the tissue edges inapproximation while a third hand applies the clip, in contrast tosuturing, where only one tissue edge needs to be held at one time whilethe suture needle is driven through it. The Kirsch clips are especiallyawkward in endoscopic applications, where access, visualization, andmaneuverability of instruments are limited. Moreover, in end-to-sideanastomosis, the tissue edges along the arteriotomy must be evertedoutwardly and approximated with the everted end of the graft vessel, amaneuver which becomes increasingly difficult as the ends of thearteriotomy are approached. In addition, due to variation in vessel sizeand structure, variation in the crimping force applied, and otherfactors, the clips may not reliably maintain the anastomotic connection.

[0012] In view of the foregoing, devices and methods are needed whichfacilitate the performance of vascular anastomosis, especially coronaryanastomosis, but which eliminate the various drawbacks of prior devices.The devices and methods should allow the surgeon to select the specificlocations on the graft and target vessels where the device is to beapplied, similar to selecting the location of each stitch in a suturedanastomosis. The devices and methods should be relatively simple toutilize without requiring an undue degree of skill and dexterity, evenat the small scale of the coronary arteries, and even in endoscopicapplications. The devices and methods should be useful for performingend-to-side, end-to-end and side-to-side anastomoses. Further, thedevices and methods should produce an anastomosis which is reliablysealed and patent, with a degree of compliance comparable to suturedanastomosis.

SUMMARY OF THE INVENTION

[0013] The invention provides surgical clips and methods that meet theforegoing needs, and that are useful not only for coronary anastomosis,but for anastomosis of a variety of other vascular structures, as wellas in ligation, wound closure and other tissue approximation andattachment applications. The invention offers a simple and convenientsolution to coronary anastomosis, allowing the anastomosis to beperformed using only two hands more quickly and easily than existingdevices, but with the hemostasis, patency, compliance and reliability ofsutures. The devices and methods of the invention are useful not only inconventional open surgical procedures, but in endoscopic, laparoscopic,thoracoscopic and other minimally-invasive procedures as well.

[0014] In a first embodiment of the invention, a surgical clip isprovided for approximating or attaching a first tissue layer to a secondtissue layer. The first and second tissue layers may be any of varioustissue structures, such as flaps of tissue adjacent to a wound orincision in a vessel, organ or body wall, but the invention isparticularly suitable for vascular anastomosis, wherein a graft vesselis joined to a target vessel. The graft vessel has a free end and agraft vessel wall defining a graft lumen. The target vessel has a targetvessel wall defining a target lumen and has an opening in the targetvessel wall, which may be an incision or other opening formed in thetarget vessel wall (for end-to-side or side-to-side anastomoses), or anopening at a free end of the target vessel (for end-to-end anastomoses).The surgical clip includes a clip body having a distal extremity with adistal end and a proximal extremity with a proximal end. The distal endis configured to penetrate through the graft vessel wall near the freeend and through the target vessel wall near the opening such that boththe distal and proximal ends of the clip body are outside the graft andtarget vessels. At least a portion of the clip body is shapable so as tocompress the graft vessel wall against the target vessel wall with thetarget vessel lumen in communication with the graft vessel lumen.

[0015] By penetrating the graft and target vessel walls, the surgicalclip provides the long-term reliability of a sutured connection. Inaddition, maintaining both ends of the clip outside of both the graftand target vessels minimizes the amount of foreign material contactingblood, eliminates the need for an internal anvil which must be removedafter clip application, facilitates visual confirmation of successfulapplication of the clip, and permits manipulation of the ends of theclip to re-apply, reposition or remove the clip. Further, the surgicalclip provides a reliable hemostatic seal by having a deformable portionwhich compresses the graft vessel wall against the target vessel wall.Moreover, through the use of a plurality of individual surgical clips,the invention provides the surgeon with the flexibility to select theideal location on both the target and graft vessel walls to which eachclip should be applied, depending upon vessel structure, condition andshape. The use of multiple independent clips also produces ananastomotic connection having compliance comparable to a suturedanastomosis.

[0016] The surgical clip may have a variety of configurations. The clipbody will generally have an outer surface against which the graft andtarget vessel walls are compressed. In one embodiment, the proximalextremity comprises a leg extending from the clip body that is movablebetween an open position spaced apart from the distal extremity and aclosed position closer to the distal extremity. The proximal extremityhas an inner surface which faces the outer surface of the clip body inthe closed position. The clip body is thus “shaped” by moving theproximal extremity into the closed position, thereby compressing thegraft and target vessel walls between the inner and outer surfaces. Theproximal extremity may be hingedly coupled to the clip body tofacilitate movement thereof, but is preferably configured to beinelastically deformed from the open into the closed position.

[0017] The movable proximal extremity may also be configured to contactor to extend across the distal extremity in the closed position. In oneconfiguration, the proximal extremity has an end portion which includestwo generally parallel segments which extend across the distal extremityin the closed position and a slot between the parallel segments forreceiving the distal extremity. The proximal extremity may also beconfigured to shield the distal end of the distal extremity in theclosed position to prevent inadvertent injury to tissue. Preferably, theproximal extremity is configured to prevent its passage through thegraft and target vessel walls. For example, the proximal extremity mayhave a cross-sectional area which is substantially larger than that ofthe distal extremity so that it cannot pass through the puncture createdby the distal extremity. The proximal extremity may also be oriented atan angle, usually at least about 90°, relative to the distal extremityto inhibit its passage through the vessel walls.

[0018] In another embodiment, the distal extremity is movable between anopen position spaced apart from the proximal extremity and a closedposition closer to the proximal extremity, and the distal extremity hasan inner surface which compresses the graft and target vessel wallsagainst the outer surface of the clip body in the closed position.Preferably, the distal extremity is inelastically deformable into theclosed position.

[0019] The distal extremity is preferably oriented such that its innersurface is at an angle of at most about 90° relative to the outersurface of the clip body. The inner surface (or the entire distalextremity) may also be arcuate in shape. The distal extremity is usuallytapered to a sharp point at its distal end to facilitate penetration ofthe graft and target vessel walls. One or more barbs may be providednear the distal end to maintain the graft and target vessel walls on thedistal extremity.

[0020] The invention also provides an applier for applying the surgicalclip. The applier includes a holding mechanism for releasably holding asurgical clip and a shaping mechanism for shaping the clip so as tocompress the graft vessel wall against the target vessel wall. Althougha variety of holding mechanisms are possible, in one embodiment theholding mechanism comprises a pin at the distal end of the applier, inwhich case the surgical clip includes a middle portion having anaperture for receiving the pin. Various types of shaping mechanisms arealso possible, but in an exemplary configuration, the clip applierincludes an inner shaft and an outer shaft axially movable with respectto each other. The clip is held by a first of the inner and outershafts, and the clip body is shaped by engagement with a second of theinner and outer shafts. In a particularly preferred aspect, the clipapplier is configured for endoscopic, laparaoscopic, thoracoscopic, orother minimally-invasive procedures, by holding the clip at the end of asmall-profile elongated shaft suitable for positioning through a smallincision, trocar sleeve, tubular port, cannula or the like. An actuatorat the proximal end of the shaft permits remote application of the clipfrom outside the body cavity.

[0021] In another embodiment, the surgical clip of the inventioncomprises a clip body, a needle portion extending from the clip bodythat has a distal end configured to penetrated the graft and targetvessel walls and to extend outside of the graft and target vessels. Theclip body is configured to prevent its passage through the graft andtarget vessel walls so that it remains outside of the graft and targetvessels. A retainer is further provided on the clip for retaining thegraft and target vessel walls on the needle portion.

[0022] In one configuration, the retainer comprises a leg attached tothe clip body and movable from an open position spaced apart from theneedle portion to a closed position closer to the needle portion. Theleg may be hingedly movable or inelastically deformable into the closedposition. Preferably, the retainer is configured to compress the graftvessel wall against the target vessel wall for reliable hemostasis. Theleg may also be configured to shield the distal end of the needleportion in the closed position.

[0023] Alternatively, the retainer may comprise a barb or otherretention device on the needle portion itself. A plurality of barbs maybe provided at spaced apart positions along the extremity of the needleportion so that the needle portion may be passed through the graft andtarget vessel walls a desired amount and the barbs will prevent theneedle portion from backing out of the vessel walls. As an alternativeto barbs, a retainer which is unidirectionally slidable or threadableonto the needle portion may be provided which is placed on the needleportion after it has been passed through the graft and target vesselwalls., The needle portion is preferably hook-shaped, J-shaped ororiented at an angle of at least about 90° relative to the clip body sothat the needle portion may be advanced through the vessel walls untilits curved portion or the clip body engages the vessel wall. The barbsor other retaining devices are positioned relative to the clip body soas to maintain the graft vessel wall in compression against the targetvessel wall.

[0024] In an additional embodiment, the surgical clips of the inventionare configured to be coupled to a flexible ring-shaped band, which ispreferably a continuous ring of suture, metal or plastic wire or strip,or other flexible material. The band defines a central opening throughwhich the graft vessel may be received. Each clip has a first portionfor engaging the graft vessel wall, and a second portion for engagingthe target vessel wall, the first and second portions being configuredto retain the graft vessel wall in sealing engagement with the targetvessel wall. A plurality of clips are positionable at spaced-apartlocations around the band. In this way, application of the clips to thevessels is accomplished by simply placing the band over the end of thegraft vessel and applying each clip to the vessel wall. The graft vesselmay then be positioned adjacent to the opening in the target vessel andeach clip applied to the target vessel wall to create a sealedanastomotic connection. The band may be either left in place, orconfigured for removal by cutting or other wise detaching the ring fromthe clips.

[0025] Preferably, the clips are coupled to the band so as to beslidable to the desired position around the perimeter of the band. Inone configuration, the clips have a loop or eyelet through which theband may be slidably received. The clips in this embodiment may have anyof various configurations suitable for vascular anastomosis, includingthose described above, as well as other configurations not specificallydescribed.

[0026] In a preferred embodiment, a method of joining a graft vessel toa target vessel according to the invention comprises providing aplurality of surgical clips each including a clip body having a distalextremity with a distal end and a proximal extremity with a proximalend; penetrating the graft vessel wall and the target vessel wall withthe distal extremity of each surgical clip such that the distal andproximal ends are disposed outside of the graft and target vessels; andshaping a portion of each clip body outside of the graft and targetvessels so as to compress the graft vessel wall against the targetvessel wall with the graft lumen in communication with the target lumen.In this way, a robust, reliable and hemostatic anastomosis is providedwhich is simple and convenient to perform using only two hands, whichminimizes the amount of foreign material in contact with the bloodstream, which allows the surgeon to place each clip in the optimumlocation based on the size, shape and condition of the vessels, andwhich provides a degree of compliance in the completed anastomosiscomparable to that of sutured anastomoses. The invention thus combinesthe ease of application, flexibility of position, reliability, andcompliance of sutures, with the convenience and quickness of surgicalclips.

[0027] Because of its simplicity and convenience, the invention isparticularly well-adapted for use in endoscopic, laparoscopic,thoracoscopic and other minimally-invasive applications. The clips maybe applied to a body structure using slender instruments positionedthrough percutaneous ports such as trocar sleeves, tubular cannulas, orsmall incisions, under direct visualization through such ports or undervideo-based visualization by means of an endoscope positioned through aport.

[0028] The nature and advantages of the invention will become moreapparent from the following detailed description taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIGS. 1A-1B are front elevational views of a surgical clipconstructed in accordance with the principles of the invention in anopen and a closed position, respectively.

[0030]FIGS. 2A and 2B are front and top cross-sectional views,respectively, of a clip applier for applying the surgical clip of FIGS.1A-1B in an open position.

[0031]FIG. 2C is a front cross-sectional view of the clip applier ofFIG. 2A in a closed position.

[0032] FIGS. 3A-3B are side cross-sectional views of a distal portion ofthe clip applier of FIGS. 2A-2C in open and closed positions,respectively, illustrating the application of the surgical clip to twoportions of tissue.

[0033]FIG. 4 is a perspective view of a distal portion of the clipapplier of FIGS. 2A-2C schematically illustrating the use of thesurgical clip in the anastomosis of a graft vessel to a target vessel.

[0034]FIGS. 5A and 5C are front elevational views of a second embodimentof a surgical clip constructed in accordance with the principles of theinvention in an open and a closed position, respectively.

[0035]FIG. 5B is a top view of the surgical clip of FIG. 5A in astraightened configuration.

[0036] FIGS. 6A-6B are side cross-sectional views of a distal portion ofa clip applier in open and closed positions, respectively, illustratingthe application of the surgical clip of FIGS. 5A-5C to two portions oftissue.

[0037] FIGS. 7A-7B are front elevational views of a third embodiment ofa surgical clip constructed in accordance with the principles of theinvention in an open and a closed position, respectively.

[0038] FIGS. 8A-8B are side cross-sectional views of a distal portion ofa clip applier in open and closed positions, respectively, illustratingthe application of the surgical clip of FIGS. 7A-7B to two portions oftissue.

[0039] FIGS. 9A-9B are front elevational views of a fourth embodiment ofa surgical clip constructed in accordance with the principles of theinvention in an open and a closed position, respectively.

[0040] FIGS. 10A-10D are side cross-sectional views of a distal portionof a clip applier in four successive configurations, illustrating theclosure of the surgical clip of FIGS. 9A-9B.

[0041] FIGS. 11A-11B are perspective views of two embodiments of ananastomosis clip system constructed in accordance with the principles ofthe invention.

[0042] FIGS. 12A-12F are front views of various embodiments ofanastomosis clips useful in the anastomosis clip system of FIGS.11A-11B.

[0043]FIG. 12G is a front view of the anastomosis clip of FIG. 12F in aclosed position.

[0044] FIGS. 13A-13C are perspective views of the anastomosis clipsystem of FIG. 11A schematically illustrating the use of the anastomosisclip system for the anastomosis of a graft vessel to a target vessel.

[0045]FIGS. 14A and 14C are front views of a further embodiment of asurgical clip according to the invention in an open and a closedposition, respectively.

[0046]FIGS. 14B is a top view of the surgical clip of FIG. 14A in astraightened configuration.

[0047]FIG. 15A is a side cross-sectional view of a clip applier forapplying the surgical clip of FIGS. 14A-14C.

[0048] FIGS. 15B-15C are side cross-sectional and top views,respectively, of a distal portion of the clip applier of FIG. 15A.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0049] A first embodiment of a surgical clip according to the inventionis illustrated in FIGS. 1A-1B. Surgical clip 20 comprises a clip body22, a distal extremity 24 attached to a first end of clip body 22 and aproximal extremity 26 attached to a second end of clip body 22. Distalextremity 24 has a sharp distal point 28 configured to penetrate one ormore layers of tissue such as a wall of a vessel, and is sufficientlyrigid to allow the distal extremity to be driven through such tissuewithout bending or buckling. Distal extremity 24 may be straight,angled, or arcuate, and may include barbs or other means of retention,as further described below. The distal extremity will have a lengthsufficient to pass through the combined thickness of all tissue layersto be fastened together using clip 20, preferably about twice thecombined thickness of the tissue layers, e.g. about 2-5 mm for coronaryanastomosis applications, or larger for application to thicker tissuessuch as the aorta, heart wall, intestines, bowel, or fascia.

[0050] Proximal extremity 26 is movable between an open position inwhich it is spaced-apart from distal extremity 24 as shown in FIG. 1A,and a closed position in which it is closer to distal extremity 24, asshown in FIG. 1B. Proximal extremity 26 may be movably attached to clipbody 22 in various ways, including by a pivot pin, living hinge or thelike, but, in a preferred embodiment, is attached by a deformable leg30, usually constructed of an inelastically deformable metal so thatonce it is placed in the closed position, proximal extremity 26 will notreturn to the open position without similar deformation. If a hingearrangement is used, a latch (not shown) may be provided on clip body 22to engage and maintain the proximal extremity in the closed position.Proximal extremity 26 has an inner surface 32 which faces an outersurface 34 of clip body 22 in the closed position. In the open position,inner surface 32 is disposed sufficiently apart from outer surface 34 tofacilitate placement of distal extremity 24 through the tissue layerswithout interference, usually being at an angle of at least about 45°,usually about 60°-120°, and preferably about 90°, relative to outersurface 34. In the open position, clip 20 thus forms a general C-shapeor U-shape, with a gap between the distal and proximal extremities. Thesize of the gap will depend upon the size and nature of the tissue towhich clip 20 is to be applied, with the distance between distalextremity 24 and proximal extremity 26 usually ranging from about0.5-8.0 mm, more particularly about 1.0-5.0 mm, and preferably, incoronary applications, about 1.5-3.0 mm.

[0051] In the closed position, inner surface 32 is preferably separatedfrom outer surface 34 by a distance of less than about the combinedthickness of the tissue layers to be fastened together with clip 20. Inthis way, the tissue layers will be compressed against one anotherbetween proximal extremity 26 and clip body 22, providing importantadvantages, as described in more detail below. The amount of tissuecompression will depend upon the nature of the tissue, the need for afluid seal, the internal pressures of any fluid within the tissue, andother factors, but will usually compress the tissue layers so as toreduce their combined thickness by at least about 10%, and preferablyabout 30%-50% from their combined, uncompressed thickness. In anexemplary embodiment suitable for coronary anastomosis, inner surface 32is separated from outer surface 34 by a distance of no more than about0.02-1.0 mm, and preferably 0.05-0.3 mm, at the closest point betweenthe two surfaces which contact the tissue layers. In other applicationsinvolving thicker tissues this distance will be greater, as needed toapply suitable compressive force to the tissues without unnecessarilycutting, crushing or otherwise damaging the tissues.

[0052] Proximal extremity 26 is preferably configured to shield distalpoint 28 of distal extremity 24 in the closed position to avoid thepossibility of the distal point causing inadvertent injury to tissue. Inone configuration, proximal extremity 26 has an outer side 36 which hasa length generally equal to that of distal extremity 24 so that theupper end 38 of outer side 36 is aligned with distal point 28 in theclosed position. Outer side 36 further has a shape selected to matchthat of distal extremity 24, having an arc generally matching that ofthe inner side of distal extremity 24 in the embodiment of FIG. 1. Inother configurations, proximal extremity 26 may include a slot, channelor aperture along outer side 36 which receives all or a portion distalextremity 24 in the closed position, or a separate sleeve or cap (notillustrated) may be placed over distal point 28.

[0053] Clip body 22 includes a means by which clip 20 may be held by aclip applier or other instrument for applying the clip to body tissue.In the embodiment of FIGS. 1A-1B, the clip holding means comprises anaperture 40 which extends through the clip body in a direction generallyparallel to the axis of movement of proximal extremity 26. Aperture 40may have various shapes and may, instead of a single aperture, includetwo or more separate apertures, depending upon the type of clip applierto be used.

[0054] FIGS. 2A-2C illustrate a clip applier 42 suitable for applyingsurgical clip 20 of FIGS. 1A-1B. Clip applier 42 has an outer shaft 44having a distal end 46, a proximal end 48, and a lumen 50. An innershaft 52 is slidably disposed within lumen 50. Inner shaft 52 has a clipholding mechanism 54 at its distal end which includes two transversepins 56 (better seen in FIGS. 3A-3B) that are received within aperture40 of clip 20. Clip 20 is held so that distal extremity 24 and proximalextremity 26 extend generally radially outward from the longitudinalaxis of inner shaft 52. As shown in the top view of FIG. 2B, a clipcover 55 is slidably mounted within outer shaft 44 parallel to a distalportion of inner shaft 52. A spring 57 disposed around inner shaft 52within lumen 50 engages a proximal end of clip cover 55 and biases it ina distal direction. In this way, clip cover 55 may be retracted in theproximal direction to place a clip 20 on pins 56 as in FIG. 2A, thenreturned to the distal position of FIG. 2B so as to retain clip 20 onpins 56 as the clip is applied. Clip cover 55 has a cut-out 58 at itsdistal end to expose distal extremity 24 of clip 20 to facilitatepenetrating tissue with the distal extremity.

[0055] An actuator handle 60 includes a pair of leaves 62 havingproximal ends 64 pivotally attached to the proximal end of inner shaft52 so that actuator handle 60 remains a fixed distance from surgicalclip 20 whether open or closed. A link 66 is pinned at one end to eachleaf 62 and at its other end to a collar 67 attached to the proximal end48 of outer shaft 44. In this way, pivoting leaves 62 inwardlytranslates outer shaft 44 distally relative to inner shaft 52 from theopen position of FIG. 2A to the closed position of FIG. 2C, therebyclosing surgical clip 20. A leaf spring (not shown) engages the innersides of each leaf 62 to bias the leaves outward into the position ofFIG. 2A. Alternatively, a tension or compression spring may be mountedaround inner shaft 52 so as to engage the proximal end of outer shaft 44and bias it proximally.

[0056] While clip applier 42 is illustrated in a single-fire designcapable of holding only one clip at a time, those of ordinary skill inthe art will understand that the clip applier of the invention may bedesigned to hold multiple clips which can be applied repeatedly withoutmanually reloading a clip into the applier after each application. Forexample, pins 56 could be configured to allow multiple clips to bestacked in parallel, with outer shaft 44 being designed to engage andclose only the outer-most clip in the stack. Alternatively, clips 20could be lined up serially in an axial channel within outer shaft 44 anda pusher could exert a distal force against the proximal end of theline. The pusher would feed clips 20 one-by-one onto pins 56 or othersuitable clip holding means after each clip is closed.

[0057] Clip applier 42 preferably is configured for use inthoracoscopic, laparoscopic, or other endoscopic surgical procedures,wherein clip holding mechanism 54 and a distal portion of outer shaft 44and inner shaft 52 are positioned through a trocar sleeve, cannula, portor small incision in the body wall, preferably between the ribs ifoperating in the thoracic cavity. The distal portion of the clip appliermust therefore have a small profile so as to fit through a small accesspassage, and a sufficient length to reach the surgical site within thebody cavity. In an exemplary embodiment, the outer diameter of outershaft 44 and the largest transverse dimension of clip holding mechanism54 are less than about 12 mm, preferably less than about 10 mm, andouter shaft 44 has a length of at least about 10 cm, preferably at leastabout 20 cm.

[0058] FIGS. 3A-3B illustrate a distal portion of clip applier 42 in theopen and closed positions, respectively. Two layers G, T of tissue to befastened together are penetrated with distal point 28 of clip 20 so thatthe edges of the tissue are disposed within the gap between distalextremity 24 and proximal extremity 24. Actuator handle 60 of clipapplier 42 is then actuated by pivoting leaves 62 inwardly, translatingouter shaft 44 distally relative to inner shaft 52. Distal end 46 of theouter shaft engages the proximal side of proximal extremity 26 anddeforms it into the closed position of FIG. 3B. The edges of tissuelayers G, T are thereby compressed between proximal extremity 26 andclip body 22. Leaves 62 contact each other and/or outer shaft 44 in theclosed position, preventing translation of outer shaft 44 beyond thatnecessary to close clip 20 with the desired degree of compression toavoid excessive crushing of tissue layers G,T. This compression oftissue is particularly advantageous when using clip 20 to performanastomosis of two vessels such as arteries. Such compression not onlyaccelerates the growing together of the two vessels, but creates animmediately hemostatic seal at the anastomosis site.

[0059] The performance of vascular anastomosis using clip applier 42 andclip 20 is illustrated in FIG. 4, which shows a graft vessel G beinganastomosed to a target vessel T. Graft vessel G may be any of a varietyof vascular structures, including blood vessels, intestines, bowel andother body ducts. The invention is particularly useful, however, foranastomosis of small blood vessel such as the coronary arteries and theconduits commonly used in coronary artery bypass grafting (CABG),including internal mammary arteries, saphenous vein grafts, radialartery grafts, gastroepiploic arteries, and other natural and artificialvascular grafts. The invention may be used either for “proximal”anastomosis—that is, the connection of the upstream end of a graft to asource of blood such as the aorta—or “distal” anastomosis, theconnection of the downstream end of the graft to a coronary artery belowa blockage in the artery. Thus, in the context of coronary anastomosis,the term “graft vessel” is used herein to mean the vascular graft usedto provide a new conduit to a coronary artery, while “target vessel” isused to mean either the arterial blood source vessel (e.g. aorta) or thecoronary artery to which the “graft vessel” is connected. In otherapplications, “graft vessel” and “target vessel” may simply refer to thetwo vessels, organs or other structures which are being connectedtogether. In addition, while FIG. 4 illustrates an end-to-sideanastomosis as is common in CABG surgery, the clips and appliers of theinvention are useful in forming end-to-end and side-to-side anastomosesas well.

[0060] As shown in FIG. 4, an end GE of graft vessel G is connected to aside wall TW of target vessel T around an opening O formed in wall TW bya surgical knife, scissors or other suitable instrument. In an arterysuch as a coronary artery, opening O is known as an arteriotomy.Initially, either inside or outside the body cavity, one or more clips20 may be attached to graft vessel end GE by puncturing distal point 28through the graft vessel wall from the exterior side toward the interiorside. Usually, this will be done with clip 20 held at the distal end ofclip applier 42, which is then positioned adjacent to the opening O intarget vessel T. Distal point 28 is then penetrated through targetvessel wall TW from the interior of the vessel outward such that thedistal edge of graft vessel end GE is approximated with the edge ofopening O. This may require slight pursing up of target vessel walls TWaround the opening and/or slight flaring or eversion of graft vessel endGE, which is accomplished using surgical forceps or other suitableinstruments. Distal extremity 24 is passed through the graft and targetvessel walls until clip body 22 is contacting the wall of graft vesselG. Actuator handle 60 of clip applier 42 is then actuated so that outershaft 44 is advanced distally, deforming proximal extremity 26 into theclosed position of clip 20′. Clip applier 42 is then removed bywithdrawing pins 56 from aperture 40. A plurality of clips 20, usuallyat least about 4, preferably 6-30, depending upon vessel size, the needfor a fluid seal, the internal pressures in the vessels, and otherfactors, are applied around the perimeter of opening O in this way untila sealed and secure anastomosis has been achieved.

[0061] It may be seen that the graft and target vessel walls arecompressed between proximal extremity 26′ and clip body 22′, providing asecure and hemostatic connection. Distal point 28′ is safely shielded byproximal extremity 26′ to prevent interference or injury to surroundingtissue. Eventually, graft vessel G and target vessel T will growtogether at the anastomosis. However, clips 20, being made of abiocompatible material such as stainless steel, titanium or titaniumalloy, tantalum, elgiloy, MP35N, or cobalt chromium-nickel alloy, may beleft in the body indefinitely to ensure that the anastomosis remainsintact.

[0062] An additional embodiment of a surgical clip according to theinvention is illustrated in FIGS. 5A-5C. Surgical clip 70 includes aclip body 72, a distal extremity 74 and a proximal extremity 76. Distalextremity 74 has a sharp distal point 78 adapted to penetrate tissue.Clip body 72 has an aperture 80 for receiving pins 56 on clip applier42. Proximal extremity 76 has an end portion 82 adapted to overlap orcross-over distal extremity 74 in the closed position shown in FIG. 5C.As illustrated in FIG. 5B, showing a top view of clip 70 in a flattenedconfiguration, end portion 82 has a bifurcated construction with a pairof parallel segments 84 separated by a space 86. Segments 84 areseparated by a distance of at least the transverse width (or diameter,if round) of distal extremity 72 to allow distal extremity 74 to bereceived within space 86 in the closed position of FIG. 5C. Proximalextremity 76 is movable between the open position of FIG. 5A and theclosed position of FIG. 5C, preferably being constructed of abiocompatible metal or other deformable material so that the proximalextremity may be inelastically deformed into the closed position.Alternatively, proximal extremity 76 may be hingedly coupled to clipbody 72 and end portion 82 may be provided with a catch (not shown)which engages distal extremity 74 in the closed position. Clip 70 mayalso be constructed of a thermally responsive shape memory alloy such asNitinol (Raychem Corp.), whereby, once distal extremity 74 has beenapplied to the target tissue, heat may be applied to clip 70 usingheated forceps or other heat-tipped probe (or by heating the distal endof the clip applier itself) so as to raise the proximal extremity to atransition temperature in which it resumes the closed position of FIG.5C.

[0063] In order to facilitate closure of clip 70 in a repeatable andpredictable hinge-like manner, a notch 87 may be provided on the innersurface of proximal extremity 76 at the junction of the proximalextremity and clip body 72. When a distally directed force is applied toend portion 82 using clip applier 42 (described below), proximalextremity 76 tends to buckle at notch 87, allowing the proximalextremity to rotate about an axis passing generally through the notchwithout excessive deformation of the proximal extremity.

[0064] Clip 70, as with clip 20 above, is constructed so as to compressthe tissue layers to which the clip is applied between proximalextremity 76 and clip body 72. Proximal extremity 76 has an innersurface 88 which faces an outer surface 90 of clip body 72 in the closedposition. The clip is preferably configured so that, in the closedposition of FIG. 5C, inner surface 88 is separated from outer surface 90adjacent to distal extremity 74 by a distance of less than the combinedthickness of all the tissue layers to which the clip is being applied,preferably about 0.05-0.3 mm for coronary distal anastomosis.

[0065] The closure of clip 70 by means of a clip applier 92 isillustrated in FIGS. 6A-6B. Clip applier 92 may be constructed similarlyto clip applier 42 of FIGS. 2-3, having an outer shaft 94 with a lumen96 extending through it, and an inner shaft 98 within lumen 94 overwhich outer shaft 94 is axially slidable. The proximal portion of theclip applier, not shown in FIGS. 6A-6B, may be constructed like that ofclip applier 42, with an actuator handle configured to translate outershaft 94 distally when actuated. A clip holding mechanism 100 is mountedto the distal end of inner shaft 98, and includes a pair of transversepins 102 configured to extend through aperture 80 in clip 70. Clip 70 isthus held in an orientation in which distal extremity 74 is disposedtransverse to, preferably about orthogonal to, the longitudinal axis ofinner shaft 98. A movable clip cover (not shown) like clip cover 55 ofFIGS. 2-3 may also be provided at the distal end of inner shaft 98 toretain clip 70 on pins 102. Proximal extremity 76 is disposed so thatthe curved outer surface of its end portion 82 is engaged by the distalend of outer shaft 94 when the outer shaft is advanced distally. Thedistal end of outer shaft 94 may be shaped so as to smoothly andcompletely deform proximal extremity 76 into the closed position of FIG.6B, including, for example, an annular undercut 104.

[0066] In use, a clip 70 is placed on pins 102 and the clip cover isallowed to slide distally over clip body 72 to retain it on the applier.Distal point 78 on clip 70 is penetrated through the tissue layers T, Gto which the clip is to be applied as shown in FIG. 6A. The actuatorhandle is then actuated, advancing outer shaft 94 distally over innershaft 98 to engage end portion 82 of clip 70 and deform it into theclosed position shown in FIG. 6B. The bifurcated end of end portion 82crosses over distal extremity 78, completely enclosing tissue layers T,G. Advantageously, tissue layers T, G. are compressed between endportion 82 and clip body 72, creating a secure and fluid-tightconnection.

[0067] FIGS. 7A-7B illustrate an additional embodiment of a surgicalclip according to the invention. Clip 110 includes a clip body 112, adistal extremity 114 and a proximal extremity 116. As in previousembodiments, distal extension 114 has a sharp distal point 118configured to penetrate tissue. Proximal extremity 116 has an aperture120 which facilitates holding the clip in a clip applier as describedbelow. Proximal extremity 116 is movable relative to clip body 112between an open position spaced apart from distal extremity 114 and aclosed position closer to distal extremity 114, shown in FIG. 7B.Preferably, the proximal extremity is made of a deformable metal whichmay be inelastically deformed into the closed position. Proximalextremity 116 has an inner surface 122 which faces an outer surface 124of clip body 112 in the closed position. Adjacent to the base of distalextremity 114, inner surface 122 is preferably spaced apart from outersurface 124 in the closed position by no more than the combinedthickness of all tissue layers to which the clip is to be applied so asto compress the tissue therebetween. Proximal extremity 116 also has anouter side 126 which is configured to shield distal point 118,preferably having a shape and dimension substantially the same as thatof distal extremity 114 so that outer side 126 lies adjacent andparallel to a substantial portion of distal extremity 114 in the closedposition. Clip body 112 has a proximal side 127 which facilitatesclosure of the clip, as described below.

[0068] The use of clip 110 with a clip applier 128 is illustrated inFIGS. 8A-8B. Clip applier 128 may have a construction like that of clipapplier 42 of FIGS. 2-3, having an outer shaft 130 with a lumen 132extending through it, and an inner shaft 134 disposed within lumen 132over which outer shaft 130 is slidable. An actuator handle (not shown)like that shown in FIGS. 2A-2C is provided at the proximal end of innershaft 134 and is coupled to outer shaft 130 such that actuation of thehandle translates outer shaft 130 distally. A clip holding mechanism 136is fixed to the distal end of inner shaft 134 and includes a recessedarea 138 configured to receive proximal extremity 116 of clip 110, and atransverse pin 140 configured to extend through aperture 120. A shelf142 along an inner edge of recessed area 138 prevents rotation of clip110 about pin 140. In this way, clip 110 is held with distal extremity114 extending generally in the radial direction from the longitudinalaxis of inner shaft 134. A clip cover 144 is slidably mounted withinlumen 132 parallel to a distal portion of inner shaft 134 and is movablefrom a proximal position shown in FIGS. 8A-8B to a distal position inwhich the clip cover extends over proximal extremity 116 of clip 110 toretain it on pin 140. A spring 146 within lumen 132 engages the proximalend of clip cover 144 and biases it into the distal position.

[0069] When the actuator handle of clip applier 128 is actuated, outershaft 130 is advanced distally so that its distal end engages proximalside 127 of clip 110, thereby deforming the clip into the closedposition shown in FIG. 8B. Distal extremity 114 is driven in a generallyrotational manner about an axis located roughly at the junction betweenproximal extremity 116 and clip body 112. Recess 138 is configured toallow distal extremity 114 to be moved completely into the closedposition without interference with inner shaft 134. After closure, clipcover 144 may be retracted away from holding mechanism 136 and clip 110then released from pin 140.

[0070] Still another embodiment of a surgical clip according to theinvention is illustrated in FIGS. 9A-9B. Surgical clip 150 includes aproximal extremity 152 and a distal extremity 154. Distal extremity 154has a sharp distal point 160 for penetrating tissue. Proximal extremity152 includes an aperture 162 to facilitate holding clip 150 in a clipapplier, as described below. Distal extremity 154 is movable between theopen position of FIG. 9A and the closed position of FIG. 9B. A notch 155is disposed at the junction of the distal and proximal extremities whichcauses distal extremity 154 to pivot in a hinge-like manner about anaxis passing generally through the base of the notch when a transverseforce is applied to distal extremity 154. Clip 150 is preferably made ofa deformable metal so as to remain in the closed position when closureforce is released. Distal extremity 154 has an inner surface 156 whichfaces an outer surface 158 of proximal extremity 152. In the closedposition, at a point adjacent to the junction of the distal and proximalextremities, inner surface 156 is preferably separated from outersurface 158 by less than the combined thickness of the tissue layers towhich clip 150 is to be applied, so as to compress the tissue betweenthe distal and proximal extremities. It is most preferred that notch 155be configured to allow the edges of the tissue to reside within thenotch, such that when the clip is closed, the layers of tissue will becompressed within the notch itself.

[0071] A distal portion of an applier 164 for closing clip 150 isillustrated in FIGS. 10A-10D. Applier 164 includes an outer shaft 166having a lumen 168, and an inner shaft 170 over which outer shaft 166 isslidable. An actuator handle like that described above in connectionwith FIGS. 2A-2C is attached to the proximal end of inner shaft 170 andcoupled to outer shaft 166 such that actuation of the handle moves outershaft 166 proximally relative to inner shaft 170. Thus, for thisembodiment, links 66 of FIGS. 2A-2C will be oriented such that the outerends pinned to leaves 66 are distal to the inner ends pinned to outershaft 166, thereby pulling the outer shaft proximally when the leavesare pivoted inwardly. In this embodiment, outer shaft 166 is rotatablymounted to collar 67 so as to be rotatable relative to inner shaft 170for reasons which will become apparent below.

[0072] A clip holding mechanism 172 is attached to the distal end ofinner shaft 170 and includes a pair of transverse pins 174 over whichclip 150 may be placed. A clip cover 176 is slidably mounted in parallelto a distal portion of inner shaft 170 and is biased distally by aspring 178 disposed within lumen 168 which engages the proximal end ofthe clip cover. In this way, after a clip is placed on pins 174 withclip cover 176 in the retracted position shown, clip cover 176 isallowed to return to a distal position covering proximal extremity 152of the clip so as to retain it on pins 174.

[0073] An anvil 180 extends distally from a distal end of outer shaft166 and has a transverse end 182 generally orthogonal to a longitudinalaxis of the outer shaft (and generally parallel to the axis of movementof distal extremity 154). In order to facilitate penetrating distalextremity 154 through the tissue to which the clip is to be applied,anvil 180 is initially positioned proximally of distal extremity 154 asshown in FIG. 10A by maintaining leaves Alternatively, anvil 180 itselfmay be mounted to outer shaft 166 so as to be pivotable or rotatable toa position suitably distant from distal extremity 154. Anvil 180 ispositioned so that transverse end 182 may be positioned distally of andgenerally perpendicular to distal extremity of 154 of the clip, asillustrated in FIGS. 10A-10B. In this way, when the actuator handle ofapplier 164 is actuated, transverse end 182 is drawn in the proximaldirection, engaging distal extremity 154 and deforming it into theclosed position shown in FIG. 10C.

[0074] A surgical clip system according to the invention is illustratedin FIGS. 11A-11B. Clip system 190 includes plurality of clips 192coupled to a flexible band 194. Clips 192 include, as shown in FIG. 12A,a proximal extremity 195, a needle portion 196 having a sharp distalpoint 198 for penetrating tissue, and a coupling 200 for attachment toband 194. Needle portion 196 is preferably curved or J-shaped with itsdistal end being at an angle of no more than about 90, and preferablyabout 45-85 relative to proximal extremity 195. Preferably, coupling 200comprises a loop, eyelet, or other structure through which band 194 maybe inserted that allows clip 192 to slide along band 194. Alternatively,coupling 200 may be configured to non-movably attach clip 192 to theband, such as by clamping or crimping onto the band, by bonding orwelding the coupling to the band, or by allowing the band to be knottedor looped through the coupling. Needle portion 196 preferably includes abarb 202 which prevents the needle portion from being removed from thetissue to which it is applied.

[0075] Band 194 is a flexible biocompatible material such as suture oran elastomeric or metallic strap, band or cable. Band 194 is preferablya continuous annular ring, but may also be a non-continuous or brokenring biased into a generally annular shape, with a retainer on each endto retain clips 192 on the band. Usually the shape of band 194 will becircular, but could alternatively be a variety of other non-circularshapes including elliptical, egg-shaped, cobra head-shaped, oval, or thelike. In any case, the flexibility of the band allows it to conform towhatever shape is desirable for the particular vascular structures withwhich it is being used. Clips 192 may be mounted to band 194 with theall needle portions 196 pointing outward as shown, or with some ofneedle portions 196 pointing inward. As shown in FIG. 11B, clips 192 mayalso be attached to band 194 so that some extend upward from the band,while others extend downward from the band.

[0076] FIGS. 12B-12G illustrate various alternative embodiments of clipsfor use in clip system 190. In FIG. 12B, a length of hypotube 204 ismounted over proximal extremity 195B. A hole 206 is disposed near theproximal end of hypotube 204 through which band 194 may be inserted. Thedistal end 208 of hypotube 204 engages the tissue through which needleportion 196B is inserted and prevents its movement upward along proximalextremity 195B. Preferably, the length of hypotube 204 is selected sothat the distance between distal end 208 and barb 202B is less than thecombined thickness of the tissue layers through which needle portion196B is inserted so that the tissue is compressed between the hypotubeand the barb.

[0077] In FIG. 12C, clip 192C has a plurality of barbs 210 arrangedsequentially along needle portion 196C. A stop 212 is disposed onproximal extremity 195C. In this way, the layers of tissue to which clip192C is applied may be translated along needle portion 196C until theouter layer contacts stop 212. Barbs 210 prevent the tissue from movingaway from stop 212. Preferably, the distance between stop 212 and barbs210 is less than the combined thickness of the tissue to allow thetissue to be compressed between the stop and the barbs.

[0078] In FIG. 12D, clip 192D has a configuration like clip 192 of FIG.12A, but in this embodiment the clip is constructed of a shape memoryalloy such as Nitinol (Raychem Corp.). At body temperature the clip hasa closed shape in which distal point 198D is close to or contactingproximal extremity 195D so as to define an enclosed space in which thetissue is retained. The clip may be isothermally transformed from anopen to a closed shape by using needle drivers or other suitableinstruments to hold distal point 198D away from proximal extremity 195Dthen release the distal point after it has been applied to tissue.Preferably, however, the clip is thermally transformed by heating theclip to the material's transition temperature using a heated probe orneedle driver until the clip assumes the closed shape.

[0079] In FIG. 12E, clip 192E has a hypotube 214 mounted to proximalextremity 195E as in FIG. 12B, and includes a retainer 216 mounted toproximal extremity 195E which abuts the distal end of hypotube 214. Adistal retainer 218 is threadably or slidably received over needleportion 196E which may be placed on the needle portion after it has beenapplied to the tissue. The tissue may be advanced along needle portion196E until it engages retainer 216, and distal retainer 218 then movedinto contact with the opposing side of the tissue to compress it betweenthe two retainers.

[0080] In FIGS. 12F-G, clip 192F has a pair of opposing needle portions220A, 220B connected by a bridging segment 222. Bridging segment 222 mayinclude a loop 224 which enhances deflection of needle portions 220.Clip 192F is movable from the open configuration of FIG. 12F to theclosed configuration of FIG. 12G wherein needle portion 220A, 220B crossover one another to define an enclosed space in which the tissue may beretained. Preferably, clip 192F is made of a superelastic shape memoryalloy such as Nitinol. In one embodiment, the clip is biased into theclosed configuration at ambient and body temperature, and isisothermally held open using appropriate instruments to apply needleportions 220 to the target tissue, then released to allow the clip toclose. In an alternative embodiment, the material has a transitiontemperature above ambient temperature at which it resumes the closedshape from the open shape. In this way, after clip 192F has been appliedto tissue in the open configuration, heat may be applied to the clipusing a heating probe or heated forceps to cause it to assume the closedconfiguration.

[0081] It should be understood that the embodiments illustrated in FIGS.12A-12G are only exemplary of the wide variety of clips that may be usedin the surgical clip system of the invention. Moreover, any of the clipsillustrated in FIGS. 1-10 above may be used in clip system 190 of FIGS.11A-11B by, for example, providing an additional aperture in the clipbody through which band 194 may extend.

[0082] FIGS. 13A-13C illustrate the use of clip system 190 in theanastomosis of a graft vessel G to a target vessel T. Initially, band194 to which clips 192 are coupled is placed over the end GE of graftvessel G. Vessel end GE is then everted over clips 192 to allow eachneedle portion 196 to penetrate the graft vessel wall from the exteriorsurface of the vessel toward the interior surface (which now facesoutwardly) as shown in FIG. 13B. Clips 192 may be repositioned alongband 194 as needed to allow selection of the optimum location at whicheach needle portion 196 penetrates the graft vessel wall based on theshape and condition of the vessel. An opening 0 is formed in the targetvessel wall corresponding to the size and shape of everted graft vesselend GE using a surgical knife or scissors. Everted graft vessel end GEis then inserted into opening 0 and the edges of vessel end GE areapproximated with the edges of opening 0. Each needle portion 196 isthen grasped with surgical needle drivers or forceps and penetratedthrough the wall of target vessel T from the interior toward theexterior thereof. The autonomy of each clip 192, the flexibility of band194 and the compliance of graft vessel G allow each clip 192 to bemanipulated and positioned to penetrate the target vessel wall at theoptimum location according to the shape and condition of the vessel.Needle portions 196 are inserted through the target vessel wall untilbarbs 202 pass through to the exterior of the vessel. The vessel wallsare thus compressed between barbs 202 and proximal extremities 195,providing a secure and hemostatic connection. Optionally, band 194 maythen be severed and removed from clip couplings 200. This ensures thateach clip is completely autonomous and unrestricted by the other clips,providing a compliant anastomosis comparable to a sutured anastomosis.

[0083] An additional embodiment of a surgical clip according to theinvention is illustrated in FIGS. 14A-14C. In this embodiment, surgicalclip 230 may be formed by cutting out a two-dimensional pattern from aflat piece of material as shown in FIG. 14B, making the clip more simpleand economical to manufacture. Clip 230 has a distal extremity 232, aproximal extremity 234, and a flanged central portion 236 therebetweenwhich has a transverse width substantially wider than the distalextremity. Distal extremity 232 has a distal point 233 configured topenetrate tissue. Proximal extremity 234 is bifurcated into twospaced-apart segments 238 defining an opening 240 therebetween in whichdistal extremity 232 may be received in the closed position of FIG. 14C.Distal extremity 232 is disposed at an angle of about 30°-120°,preferably about 60°-120°, relative to flanged central portion 236.Proximal extremity 234 is preferably at an angle of at least about 90°relative to flanged central portion 236 to facilitate closure of theclip in the manner described below.

[0084] Flanged central portion 236 is configured to be held by anapplier 242, illustrated in FIGS. 15A-15C. Applier 242 is preferablyadapted for holding a plurality of clips 230 simultaneously andautomatically feeding and applying the clips in succession. Applier 242has an inner shaft 244 having a distal end 246, a proximal end 248 and alumen 250 therebetween. An actuator 252 is mounted to the proximal end248, and has a pair of pivotable leaves 254 extending distally andoutwardly therefrom. An outer shaft 256 is slidably disposed over innershaft 244 and has a distal end 258 and a proximal end 260. A pair oflinks 262 are pinned at their outer ends to leaves 254 and at theirinner ends to a collar 263 attached to proximal end 260 of outer tube256. In this way, when the user pivots leaves 254 inwardly, outer shaft256 is translated distally relative to inner shaft 244. A flat spring(not shown) may be mounted to leaves 254 to bias them in the outwardposition, or a tension spring (not shown) may be mounted to outer shaft256 to bias it in the proximal direction.

[0085] Inner shaft 244 has an axial channel 266 along one side of innerlumen 250 configured to slidably receive a plurality of clips 230. Asillustrated in FIG. 15B, channel 266 has a width wide enough to receiveflanged central portions 236 of clips 230. A wall 268 separates channel266 from lumen 250 and has a slot 270 narrower than flanged centralportions 236, but wide enough to allow distal extremities 232 andproximal extremities 234 to slide axially. In this way, a plurality ofclips 230 may be lined up end to end in channel 266, with the distalextremity of each clip abutting the proximal extremity of an adjacentclip. A pusher 272 is mounted to the proximal end of inner shaft 244 andis biased distally by spring 274. Pusher 272 has a distal end 276configured to push against the most proximal clip in channel 266,thereby urging all of clips 230 toward distal end 246.

[0086] Channel 266 is angled laterally as it approaches distal end 246,and terminates at an abutment 278 against which the distal most clip230′ is positioned. This exposes most of distal extremity 232′ tofacilitate applying it to one or more layers of tissue, and positionsproximal extremity 234′ adjacent to distal end 258 of outer shaft 256.In this way, when actuator 252 is actuated, outer shaft 256 engagesproximal extremity 234′ of clip 230′ and urges it into the closedposition of FIG. 14C. As shown in FIG. 15C, slot 270 widens at thedistal end of channel 266 to a width wider than flanged central portion236′, allowing clip 230′ to be withdrawn from channel 266 after it hasbeen closed. When clip 230′ has been withdrawn, the next clip in line isurged distally by pusher 272 until it contacts abutment 278, where it isready for application. Thus, a plurality of clips may be appliedsuccessively to a surgical site within a body cavity without removingthe applier from the body cavity to reload clips.

[0087] Clip applier 242 may be preloaded with a plurality of clips 230and disposed of upon application of all of the clips. Alternatively,inner shaft 244 may be detachable from actuator 252, allowing theactuator and outer shaft to be sterilizable and reusable, with innershaft 244 being replaced or reloaded with clips between uses. Inaddition, clip applier 242 is preferably configured for endoscopic uses,having a length and profile suitable for positioning through a trocarsleeve or other small percutaneous access port into a body cavity.

[0088] While the above is a complete description of the preferredembodiments of the invention, various alternatives, substitutions,modifications, and equivalents of the embodiments described are possiblewithout departing from the principles thereof. Therefore, nothingdisclosed above should be taken to limit the scope of the invention,which is defined by the appended claims.

What is claimed is:
 1. A surgical clip for sealingly joining a graftvessel to a target vessel, the graft vessel having a graft vessel walldefining a graft lumen, the target vessel having a target vessel walldefining a target lumen, the surgical clip comprising: a clip body; aneedle portion extending from the clip body and having a distal endconfigured to penetrate the graft and target vessel walls and extendoutside of the graft and target vessels, the clip body being configuredto prevent passage of the clip body through the graft and target vesselwalls; and a retainer disposed outside of the graft and target vesselsfor retaining the graft and target vessel walls on the needle portion.2. The surgical clip of claim 1 wherein the retainer comprises a legattached to the clip body movable between an open position spaced apartfrom the needle portion and a closed position closer to the needleportion for retaining the graft and target vessel walls thereon.
 3. Thesurgical clip of claim 2 wherein the retainer is configured to compressthe graft vessel wall against the target vessel wall.
 4. The surgicalclip of claim 3 wherein the retainer has an inner surface and the clipbody has an outer surface which faces the inner surface in the closedposition, the retainer being configured to compress the graft and targetvessel walls between the inner and outer surfaces.
 5. The surgical clipof claim 4 wherein the needle portion is disposed at a an angle of nomore than about 120° relative to the outer surface of the clip body inthe open position.
 6. The surgical clip of claim 2 wherein an endportion of the retainer is configured to extend across the needleportion in the closed position.
 7. The surgical clip of claim 6 whereinthe retainer has two generally parallel segments for extending acrossthe needle portion on opposing sides thereof and a slot between theparallel segments for receiving the needle portion.
 8. The surgical clipof claim 1 wherein the retainer comprises at least one barb on theneedle portion.
 9. The surgical clip of claim 1 wherein the needleportion is hook-shaped.
 10. The surgical clip of claim 2 wherein theretainer shields the distal end of the needle portion in the closedposition.
 11. The surgical clip of claim 2 wherein the retainer contactsthe needle portion in the closed position.
 12. The surgical clip ofclaim 1 wherein the clip body includes a middle portion configured to beheld by a clip applier for applying the clip.
 13. The surgical clip ofclaim 2 wherein the middle portion has a substantially largercross-sectional area than the needle portion.
 14. The surgical clip ofclaim 12 wherein the middle portion has an aperture therein forreceiving a portion of the clip applier.
 15. The surgical clip of claim1 wherein the clip body includes a coupling for attachment to a flexibleband.
 16. The surgical clip of claim 1 wherein the needle portion has alength of at least about twice the combined thickness of the graft andtarget vessel walls.
 17. An anastomosis device for sealingly joining agraft vessel to a target vessel, the graft vessel having a free end anda graft vessel wall defining a graft lumen, the target vessel having atarget vessel wall with an opening therein and defining a target lumen,the anastomosis device comprising: a flexible ring-shaped band defininga central opening in which the graft vessel may be received; and aplurality of clips coupled to the band and positionable at spaced apartlocations around the band, each clip having a first portion for engagingthe graft vessel wall and a second portion for engaging the targetvessel wall, the first and second portions being configured to retainthe graft vessel wall in sealing engagement with the target vessel wall.18. The anastomosis device of claim 17 wherein the clip has a distalextremity for penetrating the graft and target vessel walls.
 19. Theanastomosis device of claim 18 wherein the clip is generallyhook-shaped, the distal extremity being oriented at an angle of at leastabout 90° relative to a proximal portion of the clip.
 20. Theanastomosis device of claim 17 wherein the clip has a loop for slidablyreceiving the band.
 21. The anastomosis device of claim 18 wherein atleast a portion of the clip is movable between an open and a closedposition so as to retain the graft and target vessel walls on the distalextremity.
 22. The anastomosis device of claim 21 wherein the movableportion of the clip is configured to remain outside of the graft andtarget vessels when the distal extremity has penetrated the graft andtarget vessel walls.
 23. The anastomosis device of claim 22 wherein thedistal extremity has a distal end, the distal end being configured to bedisposed outside the graft and target vessels when the distal extremityhas penetrated the graft and target vessel walls.
 24. The anastomosisdevice of claim 21 wherein the movable portion of the clip is deformablefrom the open position to the closed position.
 25. The anastomosisdevice of claim 21 wherein the movable portion is spaced apart from thedistal extremity in the open position and is closer to the distalextremity in the closed position.
 26. The anastomosis device of claim 21wherein the distal extremity is movable between the open and closedpositions.
 27. The anastomosis device of claim 18 further comprising aretainer for retaining the graft and target vessel walls on the distalextremity.
 28. The anastomosis device of claim 27 wherein the retainercomprises at least one barb on the distal extremity.
 29. An anastomosissystem for sealingly joining a graft vessel to a target vessel, thegraft vessel having a free end and a graft vessel wall defining a graftlumen, the target vessel having a target vessel wall with an openingtherein and defining a target lumen, the anastomosis system comprising:at least one anastomosis clip including a clip body having a distalextremity with a distal end and a proximal extremity with a proximalend, the distal end being configured to penetrate through the graft andtarget vessel walls; and a clip applier including a holding mechanismfor releasably holding the anastomosis clip such that the distal end maybe passed through the graft vessel wall near the free end and throughthe target vessel wall near the opening such that both the distal andproximal ends of the clip body are outside the graft and target vessels,and a shaping mechanism disposed outside the graft and target vesselsfor shaping at least a portion of the clip body so as to compress thegraft wall against the target vessel wall with the target vessel lumenin communication with the graft vessel lumen.
 30. The anastomosis systemof claim 29 wherein the proximal extremity comprises a leg extendingfrom the clip body movable between an open position spaced apart fromthe distal extremity and a closed position closer to the distalextremity.
 31. The anastomosis system of claim 30 wherein the proximalextremity shields the distal end of the distal extremity in the closedposition.
 32. The anastomosis system of claim 29 wherein the distalextremity is movable from an open position spaced apart from theproximal extremity and a closed position closer to the proximalextremity.
 33. The anastomosis system of claim 32 wherein the distalextremity has an inner surface and the clip body has an outer surfacewhich faces the inner surface in the closed position, the distalextremity being configured to compress the graft and target vessel wallsbetween the inner and outer surfaces in the closed position.
 34. Theanastomosis system of claim 33 wherein the inner surface of the distalextremity is disposed at a an angle of no more than about 120° relativeto the outer surface of the clip body in the open position.
 35. Theanastomosis system of claim 29 wherein the clip body includes a middleportion configured to be held by the clip applier.
 36. The anastomosissystem of claim 35 wherein the middle portion has a substantially largercross-sectional area than the distal extremity.
 37. The anastomosissystem of claim 36 wherein the clip applier has a pin on a distal endthereof and wherein the middle portion of the clip body has an aperturetherein for receiving the pin.
 38. The anastomosis system of claim 35wherein the holding mechanism is configured to hold the middle portionin a stationary position relative to the clip applier as the shapingmechanism shapes the clip body.
 39. The anastomosis system of claim 29wherein the clip applier is configured to hold a plurality of clips. 40.The anastomosis system of claim 39 wherein the clip applier has an axialchannel and the clip has a middle portion having a width wider than thedistal extremity, the middle portion being configured to be axiallyslidable along the axial channel.
 41. The anastomosis clip of claim 29wherein the clip applier has an inner shaft and an outer shaft movablewith respect to each other, the clip body being held by a first ofeither the inner or the outer shaft and the clip body being shaped by asecond of either the inner or the outer shaft.
 42. A method of sealinglyjoining a graft vessel to a target vessel, the graft vessel having afree end and a graft vessel wall defining a graft lumen, the targetvessel having a target vessel wall defining a target lumen and having anopening therein, the method comprising: providing a plurality ofanastomosis clips each including a clip body having a distal extremitywith a distal end and a proximal extremity with a proximal end;penetrating the graft vessel wall and the target vessel wall with thedistal extremity of each anastomosis clip such that the distal andproximal ends are disposed outside of the graft and target vessels; andshaping a portion of each clip body outside of the graft and targetvessels so as to compress the graft vessel wall against the targetvessel wall with the graft lumen in communication with the target lumen.43. The method of claim 42 wherein the shaping step comprises moving theproximal extremity of the clip body from an open position spaced apartfrom the distal extremity to a closed position closer to the distalextremity.
 44. The method of claim 42 wherein the shaping step comprisesmoving the distal extremity of the clip body from an open positionspaced apart from the distal extremity to a closed position closer tothe distal extremity.
 45. The method of claim 42 wherein the shapingstep comprises generally inelastically deforming a portion of the clipbody.
 46. The method of claim 42 wherein the shaping step comprisescompressing the graft and target vessel walls between an inner surfaceof the distal extremity and an outer surface of the proximal extremity.47. The method of claim 42 further comprising shielding the distal endof the distal extremity outside the graft and target vessels afterpenetrating the graft and target vessel walls.
 48. The method of claim42 wherein the target vessel comprises a coronary artery on the heart.49. The method of claim 48 wherein the graft vessel comprises a vesselselected from the group including mammary arteries, vein grafts,arterial grafts, and artificial grafts.
 50. The method of claim 42wherein the step of penetrating comprises, after penetrating the graftvessel wall, selecting a position for penetrating the target vesselwall, and positioning the distal extremity relative to the target vesselwall so as to penetrate the target vessel wall at said position.
 51. Themethod of claim 42 wherein the step of penetrating is performed withoutcontinually maintaining the graft vessel wall in contact with the targetvessel wall.
 52. The method of claim 51 further comprising positioningthe graft vessel wall relative to the target vessel wall afterpenetrating the graft vessel wall but before penetrating the targetvessel wall.
 53. The method of claim 52 wherein the target vessel is ina body cavity, the step of penetrating comprising penetrating the graftvessel wall outside the body cavity, positioning the graft vessel in thebody cavity, and penetrating the target vessel wall in the body cavity.54. The method of claim 52 wherein the target vessel is in a bodycavity, the step of shaping being performed with an elongated instrumentpositioned in the body cavity through a percutaneous penetration. 55.The method of claim 54 wherein the elongated instrument is positionedthrough a tubular cannula into the body cavity.
 56. The method of claim54 wherein the elongated instrument comprises a clip applier.
 57. Themethod of claim 56 further comprising repeating the steps of penetratingand shaping for a plurality of anastomosis clips without removing theclip applier from the body cavity.